Afghan National Police (ANP) officers take part in a drill at a training centre near the German Bundeswehr army camp Marmal in Mazar-e-Sharif, northern Afghanistan December 11, 2012.

REUTERS/Fabrizio Bensch

KABUL (Reuters) – U.S. Defense Secretary Leon Panetta met top commanders in Kabul on Wednesday to finalize options for President Barack Obama on how many troops to keep in Afghanistan after the NATO mission ends in 2014 and the war is declared over.

Panetta has not disclosed how large a force he believes will be needed, but one U.S. official has told Reuters that figures as low as 6,000 U.S. troops were under consideration. President Barack Obama could make a decision in the coming weeks.

General John Allen, the top U.S. and NATO commander in Afghanistan, said before closed door talks that he looked forward to a candid conversation with Panetta. The defense secretary told Allen and other commanders he was trying to â€œtee upâ€ options for Obama.

â€œThe size of that enduring presence is something that the president is going to be considering over these next few weeks,â€ Panetta told troops in Kuwait earlier in the day before boarding his flight to Kabul.

Panetta, on his fifth trip to Afghanistan as defense secretary, was scheduled to meet Afghan President Hamid Karzai.

Fresh from a re-election victory, Obama has made clear his intention to end the 11-year-old war and bring the vast majority U.S. forces home by the end of 2014.

But his decision is complicated by a still-resilient Taliban and intelligence showing its al Qaeda allies aim to return in larger numbers to Afghanistan. Worries about the capabilities of Afghan security forces have also raised questions about whether they can operate on their own if too many U.S. troops withdraw.

IMPERFECT, WITH WARTS

U.S. Major General Lawrence Nicholson, who runs day to day operations for the NATO-led mission in Afghanistan, acknowledged that Afghan security forces had their share of imperfections but played down concerns about the end-2014 deadline.

A former commander in Iraq, Nicholson praised Afghan forces, who he said were better fighters than the Iraqis.

â€œWhatâ€™s it going to look like on 1 January, 2015? It will be imperfect. It will be flawed. It will have warts,â€ he said, briefing reporters traveling with Panetta. â€œBut itâ€™s going to work.â€

One factor that might cause the U.S. military to keep more troops in Afghanistan would be the need to supply a big stock of â€œenablersâ€ for the Afghan forces.

But Nicholson said his goal was to make the Afghan forces self-sufficient, with the exception perhaps of assisting them with close air support.

â€œAny enablers that we have in the country after 1 January â€˜15 are to be here in support of coalition forces. Theyâ€™ll be here for us,â€ Nicholson said. â€œWeâ€™ve got 24 months to get this right and weâ€™re well on the road.â€

There are 68,000 U.S. troops in the country, a figure expected to gradually decline over the next two years at a pace that will be decided after the size of the post-2014 mission has been set.

A report released by the Pentagon this week noted a slight rise in Taliban attacks between April and September this year, compared with 2011. But Nicholson said that the number of attacks against the NATO-led force fell 20 percent from October to December.

â€œIâ€™m not one of those guys who are going to sit here and tell you that the Taliban is defeated, or that theyâ€™re gone, or going way,â€ Nicholson said. â€œBut it was a tough year for the Taliban.â€

Panetta noted that the number of so-called insider attacks against U.S. forces by Afghan security forces had declined, from a high of about 12 in August to two in November.

Those attacks, some of which were claimed by the Taliban, were deeply demoralizing and led Allen to revise security protocols and bolster sensitivity training of NATO forces to avoid accidentally provoking their Afghan counterparts.

â€œSo the steps that were put in place to try to deal with that threat I believe have been effective in trying to lower the incidents of insider attacks,â€ he told reporters at the start of this weekâ€™s trip.